A thermo-clamp was a device owned by Sarah Jane Smith.
In 2010 a meteor was falling to Earth and had a strong possibility of containing germ pathogens. That's why Sarah Jane wanted to destroy the germs. She asked Clyde Langer to fetch the thermo-clamp and Rani Chandra to get the bio-coolant. Then they went to the place where the meteor landed. However when Sarah Jane asked Rani Chandra to use the bio-coolant, Ruby White had already used her own bio coolant spray on the meteor and destroyed the germs that it contained. (TV: Goodbye, Sarah Jane Smith)